Form jacks



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FORM JACKS 2 Sheets-Sheet 1 Aug. 23, 1960 Filed sept. 24, 1959 INVENTOR.

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ATTORNEYS 2,949,982 Patented Aug. 23, 1960 FORM JACKS Waiter H. Cobi, 45Upland St., Port Chester, NX.

Filed Sept. 24, 1959, Ser. No. 842,122

Claims. (Cl. 189-37),

The present invention relates to devices for supporting concrete formboards between spaced floor joists and more particularly to improvementsin devices of the type illustrated and described in my U.S. LettersPatent 2,866,252, issued December 30, 1958, and entitled Concrete FormHolders.

lt is a common practice in building construction to lay oors ofreinforced concrete on floor joists mounted in spaced relation betweenthe main load bearing beams of the building structure. Such joists areusually solid or open web metal I-beam. Ply-Wood form boards are mountedbetween the upper flanges of the joists to provide a temporary door forthe buggies in which the wet concrete is transported and provide asupport for the poured concrete until it has set. After the boards havebeen mounted between the upper iianges of the I-bearn joists, a mat ofreinforcing rods is placed over the top of the joists and form boards.After the concrete has set, the plywood forms are removed leaving thereinforced concrete slab supported on the joists to form the floor.

My Patent 2,866,252 illustrates and describes a collapsible form-jackfor supporting the ply-wood form boards which may be easily and quicklyapplied to and removed from the I-beam joists with which they are used.The form-jackets extend between the joists with their ends supported bythe lower flanges thereof and each jack com prises separate built-upbeam sections having overlapping inner ends pivotally connected to eachother. Thus, the built-up beam sections of the form-jacks may hinge toadapt the jacks to be inserted between the joists. After a form jack hasbeen positioned between spaced joists, the built-up beam sections arerocked into horizontal alignment and locked by pins inserted in alignedslots in the upper edges of the overlapping sections. Load bearing padsare mounted on the sections of the form-jack adjacent its ends whichproject upwardly therefrom and support the form boards. Such form-jackshave been used extensively and have proved to operate satisfactorily.

One of the objects of the present invention is to provide an improvedform-jack of the type indicated which facilitates the insertion andremoval ofthe jack to and from the joists with which it is used.

Another object is to provide a form-jack of the type indicated which isadapted to hinge intermediate its end upon the manual application of aforce at its opposite ends -to adapt the jack to be inserted between theilanges of spaced joists and spring back to its extended position whenreleased.

Another object is to provide an improved construction in a form-jackwhich faciiitates locking the jack in its operative position betweenjoists and unlocking the jack to permit it to hinge.

Another object is to provide a form-jack of the type indicated having aminimum number of interchangeable parts and which may be easily andquickly adjusted to iit joists of different heights and spacings.

Still another object is to provide a form jack of theY type indicatedwhich is of simple, compact, rugged and light-weight construction andone which is economical to manufacture and reliable in operation.

These and other objects will become more apparent from the followingdescription and drawings in which like reference characters denote likeparts throughout the several views. It is to be expressly understood,however, that the drawings are for the purpose of illustration only andare not a definition of the limits of the invention, reference being hadfor this purpose to the appended claims.

In the drawings:

Figure 1 is a side elevational View partly in section of a form jackincorporating the novel features of the present invention and showingthe relationship of the parts When the jack is locked in positionbetween spaced joists to support a form board;

Figure 2 is a plan View of the form-jack partly in section and showingthe pivoted sections of the upper strut connected by a flexible springstrip;

Figure 3 is a bottom plan view of the spring strip connecting thesections of the lower strut and showing the key hole which cooperateswith the locking bar.

Figure 4 is a transverse sectional view taken on line 4 4 of Figure land showing the inverted U-shaped form of the load supporting stanchionat one end of the jack and the manner of mounting the strut sectionstherebetween;

Figure 5 is a view similar to Figure l showing the formjack hingedintermediate its ends to adapt it to be mounted between the spacedjoists;

Figure 6 is a view similar to Figure 5 and showing the manner in whichthe form-jack is locked in extended position between the joists;

Figure 7 is a view similar to Figure 6 showing the locking bar inunlocking position and being pulled to remove the jack from the spacedjoists;

Figure 8 is a side elevational view of one end of the jack shown appliedto an open web joist and an adapter for adjusting the height of thestanchions for beams of different heights; and

Figure 9 is a transverse sectional view taken on line 9-9 of Figure 8 toshow the manner of mounting the adapters on the stanchions.

Referring now to the drawings, Figure l illustrates a reinforcedconcrete floor construction and the form-jack of the present invention.The door construction comprises spaced lloor joists 1d and 143', onlytwo being shown, which are supported at their ends on the load carryingbeams of the building structure, not shown. The joists 10 and 10 may beof the solid web i-beam type, as shown in Figures 1 to 7, or of the openweb type illustrated in Figures 8 and 9. In either case, the joists 1i)and. 10 each have upper and lower anges il and 12 and the joists arespaced from each other a predetermined fixed distance, for example, 24inches on centers. A form board 13 is shown supported between the spacedfloor joists l0 and 10 by form-jacks 14 constituting the subject matterof the present invention. Preferably, the form board 13 extends underthe flanges 11 of the joists 19 and 10 as illustrated in Figure l, toreduce the dripping of wet concrete and the board, for example, may betwentytwo inches wide and from four to eight feet long and overlaps theflanges about one-half inch. Overlying the top of the form boards 13 andtop ilanges 11 of the joists titl and 10 is a mat 15 of reinforcingsteel mesh immersed in a concrete mass 16 poured on the form boards andjoists to form a oor.

Each form-jack 14 comprises upright stanchions 17 and 18 at each endwith upper and lower struts 19 and 20 extending therebetween and alocking bar 21 extending through the struts.

Struts 19 and 20 are adapted to hinge when released by the locking barto collapse the jack for insertion and removal, but may be locked inspaced relation by the locking bar. When the struts are locked in spacedrelation, they act against each other to resist bending and ycollapse ofthe form-jack. ln other words, when the hinge portions of the struts 19and 2) are held in spaced relation they cannot buckle relative to eachother. In the illustrated embodiment, the struts 19 and 2@ are shownsubstantially parallel when in locked position, but they may extend atan `angle to each other or at other angles to the stanchions 17 and 1Sthan the 90 angle illustrated.

As shown in Figure 4, each upright stanchion 17 and 1S is in the form ofan inverted U-shaped yoke having spaced parallel sides 22 and 22a with aconnecting top plate 23 and outwardly projecting anges 24 and 25 at thelower ends of the sides. A base plate 26 underlies the flanges 24 and 25of each stanchion 17 and 1S and is attached thereto `as by means `ofbolts 27. Each base plate 26 projects outwardly beyond its stanchion 17and 18 to provide a foot 28 adapted to rest on the lower iiange 12 ofthe door joists 10 or 10. Base plates 26 of diiferent length may beattached to the stanchions 17 and 18 to accommodate the iiange 12 or"particular floor joists and 16. The transverse top plates 23 of theinverted U-shape stanchions 17 and 1S provide spaced supports for theform board 13 adjacent each end of the form-jack. The sides 22 and 22aof each stanchion 17 and 1S have aligned holes 36 and 75 oiset bothvertically and laterally for a purpose as will later appear.

The upper strut 19 comprises separate rigid sections 29 and 36 pivotallyconnected at one end to the respec-` tive stanchions 17 and 18. In theillustrated embodiment, each rigid section 29 and 36 is in the form of achannel having a web 31 extending between the spaced sides 22.

and 22a of stanchion 17 or 1S and depending ilanges 32 and 33 adjacentthe sides. The flanges 32 and 33 of rigid channel sections 29 and 30have a series of aligned holes 34, 34', 34, etc., spaced at ixedincrements from one end corresponding to usual increments of spacingbetween joists 1t) and 16. 30 is pivotally connected to its stanchion 17or 1S, respectively, by a pin 35 extending through aligned holes 36 inthe sides 22 and 22a of the stanchion and one set of aligned holes 34,34', 34, etc., in anges 32 and 33 of a strut section. As shown in Figure4, the pin 35 is staked adjacent one end to provide a lug 37 forengaging one side 22 of the stanchion and a spring clip 38 is mounted onthe other end of the pin for engaging the other side 22a of thestanchion to hold the pin in position. This construction permits thepins 35 to be removed for adjusting the length of the form-jack whenrequired. The inner ends of the rigid sections 29 and 30 of upper strut19 are connected by a spring hinge illustrated as a strip of springmaterial 40 attached to webs 31 of the rigid sections 29 and 30 byrivets 41. Strip 40 yieldingly holds the sections 29 and 30 inhorizontal alignment but yields to adapt the strut 19 to hingeintermediate its ends. The spring strip 40 may be formed of any suitablematerial such as spring steel.

The lower strut 20 is of a construction similar to the upper strut 19,but reversed thereto, and comprises rigid sections 42 and 43 of channelform positioned between the sides of the upright stanchions 17 and 18below the upper strut 19. Each rigid section 42.and 43 of the lowerstrut is connected to its respective stanchion 17 or 18 by a pluralityof pins 44 and 45 of the same construction as the pin 35 and removablysecured to the stanchions by lugs 37 and a spring clip 38. Thus, therigid sections 42 and 43 can move only as a unit with the stanchions 17and 18 to which it is connected. The inner ends of the rigid sections 42and 43 of the lower strut 20 also are connected to hinge by a springstrip 46 attached to the section by means of rivets 47. Thus, the springstrip 46 yieldingly holds the sections 42 and Each rigid section 29 and-43 of the lower strut 20 in alignment, but yields to permit the strut tohinge intermediate its ends.

In the form-jack 14 illustrated, the inner ends of the rigid sections29, 30 and 42, 43 of each strut 19 and 20 are spaced apart ive inchesand connected by a spring steel strip nine inches long, three incheswide and one thirty-second of an inch thick and overlaps the sectionstwo inches with the rivets spaced one inch apart. It will also beobserved that the stanchions 17 and 18 at each end and the upper andlower struts 19 and 20 are identical, brut reversed, so that the partsare interchangeable.

The spring lstrips 41 and 46 of struts 19 and 20 are held insubstantially parallel relation to each other or released for hingingmovement by the locking bar 21. The locking bar 21 is illustrated in theform of a rod extending through holes 50 and 51 in the spring strips 46and 46, respectively. The hole 50 is of circular form to Y closely t thelocking bar 21, but the hole 51 in the strip of spring strips 4l) and46.

46 has a slot 52 at one side to provide a key hole for releasing thelocking bar 21 as will later appear. Locking bar 21 has shouldersoverlying the opposite sides In the illustrated embodiment the shouldersare in the form of pins 53 and 54 extending through the locking bar 21in parallel relation at opposite sides of the spring strip 40, a pin 55extending through the bar parallel with pins 53 and 54 and overlying theunderside of the spring strip 46 and a shorter pin 56 overlying the topof spring strip 46 and projecting from one side of the locking bar atright angles to the other pins 53, 54 and 55 and of a length to tit andmove through the slot 52 at one side of the key hole S1.

Locking bar 21 also has an actuating pin 57 extending through the bar inspaced relation to the lower spring strip 46. Thus, when the locking bar21 is moved to the locking position illustrated in Figure l, the pins53, 54 and 55 extend longitudinally of the struts 19 and 26 and theshorter pin 56 extends at right angles to the other pins at oppositesides of the spring strips 46 and 46, respectively. On the other hand,when the locking bar 21 is turned 90 from the position illustrated inFigure l to the position illustrated in Figure 5, the pins 53 54 fr, and55 are positioned transversely of the strip and the shorter locking pin56 is aligned with the slot 52 at the side of the key hole 51.

Figures 8 and 9 illustrate the form-jack 14 applied to an open web typeof joist 59 and adapter pads 66 whichv may be mounted on the stanchionsto adjust their height. The open web joist as illustrated in Figures 8and 9 comprises an upper pair of angle iron strips 61 and 62 and a lowerpair of rod 63 and 64 with the reverse bends 65 and 66 of alongitudinally extending sinuous rod 67 positioned between the pairs ofupper strips and lower rods and attached thereto as bywelding. Thus, thepairs of angle iron strips 61 and 62 and rods 63 and 64 constitute theflanges of the joist 59 and the sections of the longitudinally extendingsinuous rod between the reverse bends and 66 constitute bracing strutsbetween the pairs of angle iron strips and rods and provide an openlweb. As shown in Figure 8, an auxiliary foot plate 68 is bolted to thefoot 26 of an upright stanchion 17 of the form-jack which overlies andrests on the lower r rods 63 and 64 and the stanchion supports a formboard 13 under the horizontal flange of an upper angle iron,

strip 62. Advantageously, the auxiliary foot plate 68 has a hole 69overlying the space between rods 63 and 64 and through which a spike orbolt may be dropped to releasably lock the jack to the joist.

When a solid web or open web joist 10 or 59 is used of a height greaterthan the height of the stanchions 17 and 18, adapter pads 60 areprovided for adjusting the'- height of the stanchions. As shown mostclearly in Figure 9, the adapter pads 60 are of inverted U-shaped formhaving sides 70 and 71 of a width to t over the' sides 22 and 22a of thestanchions and a weight bearing cross-piece 72 for supporting a formboard 13. The sides 70 and 71 of adapter 60 have aligned holes 73 and74, `adapted to align with the holes 36 and 75 in the sides of thestanchions 17 and 18 and similar holes 73' and 74' oiset vertically fromholes 73 and 74. The pin 35 for pivotally mounting its section of theupper strut 19 extends through the hole 73 or 73' and a pin 76 extendsthrough holes 74 lor 74' and the holes 75 in the sides of the stanchionto iixedly attach the adapter pad to the stanchion. By positioning thedifferent holes 73, 74 or 73', 74 in alignment with the holes 36 and 75in the sides of the upright stanchion 19 or 20, the height of thestanchion may be increased in increments corresponding to the incrementsof increase in the height of the joist used, as for example, l() and l2inch joists. One form of the invention having now been described indetail, the mounting of the jacks in position between joists or 59 isnext explained.

For any particular building the joists 10 and 10' will be of aparticular height and the joists will be spaced a particular distance.For example, the joists may be eight, ten or twelve inches high, and thejoist may be spaced apart from twenty-four to thirty inches. Each of theform-jacks 14 to be used on the job is adjusted for these articularspecications. To this end, the height of the stanchions 17 and 18 areadjusted when required by mounting adapters 60 thereon at the properheight by inserting pins 35 and 76 through the proper holes 73, 74 or73', 74', see Figure 9. The length of the jack 15 is adjusted bychanging the position of the stanchions 17 and 18 along the struts 19and 20 by removing the pins 35, 44 and 45 and inserting them through theparticular holes 34, 34', 34", etc., in the anges 32 and 33 of the rigidchannel sections 29, 30 `and 42, 43. Base plates 26 of the properdimensions also are bolted to the flanges 24 and 25 on the stanchions 17and 18 so as to support the form-jack on the anges 12 of the particularjoists 10 or 59. When the form-jacks 14 are so adjusted they willsupport the form boards 13 at the desired height between the anges 11 ofthe I-beam joists 10 or 59.

Each form jack 14 is mounted between joists 10 or 59 by turning thelocking bar 21 so that the locking pin 56 is in alignment with the keyhole slot 52 and positioning the foot 28 of one stanchion 17 on thelower ange 12 of one of the joists. The opposite stanchion 18 is thenmanually tilted toward the stanchion 17 to cause the jack to hingeintermediate its ends as illustrated in Figure 5. During such tilting,the spring strip 46 of the lower strut exes between the rigid sections4-2 and 43. However, to permit such flexing the stanchion 18 must tiltinwardly toward the stanchion 17 so that the hinge pins 35 will bespaced a horizontal distance less than the distance between the pins 44.Thus, the upper strut 19 must hinge to a greater degree than the lowerstrut 20 as illustrated in Figure 4 and such relative movement of thestruts is permitted by the pivot pins 35 and the free movement of thelocking bar 21 relative to the lower strut. The relative tilting of thestanchions 17 and 18 permits the foot 28 of the right hand stanchion 18to pass by the upper flange 11 of the opposite joist 10'. After the foot28 passes the ange, the stanchion 18 may be manually released and thespring strips 40 and 46 will spring back to their initial position andmove the struts 19 and 20 to substantially parallel relationship toengage the foot 28 of stanchion 18 with the flange 12 of the joist 10'as illustrated in Figure 6.

The jack 14 is then locked in its operative position between the joists10 and 10 by raising the locking bar 21 with the locking pin 56 inalignment with the key hole slot 52. This operation is shown beingperformed manually in Figure 6, but it will be understood that it wouldbe performed by an extension pole or may be performed from above by aman standing on the top of the oor joists 10 and 10. The lockingoperation is completed by moving the locking bar 21 from the positionillustrated in Figure 6 6to that illustratedin Figure l with theVlocking pin 56 moving through the key hole slot 52 to overlie the springstrip 46 and then turning the locking bar through an angle of The pins53 and 54 on the locking bar then extend longitudinally on oppositesides of the spring strip 40, the pin 55 extends longitudinally alongthe underside of the spring strip 46 and the shorter locking pin 56 eX-tends transversely of the spring strip 46 at the top thereof.

When locking bar 21 is in locking position, the upper and lower struts19 and 20 are positively held in parallel relation which prevents thejack from hinging intermediate its ends. If a force couple is applied tothe' upright stanchions 17 and 18, tending to hinge the jack 15 betweenits ends, a compressive force is produced on one strut 19 or 20 and atension force is produced on the other strut. Thus, a compressive forceon the upper strut 19 tending to buckle the strut is transmitted throughthe locking bar 21 to the other lower strut 20, which is in tension, andopposes the buckling of the upper strut. As stated above, one of thestruts, such as the upper strut 19, must buckle and move relative to theother lower strut 20 before the jack 14 can hinge intermediate its endsand the pivot pins 35 for the upper strut must move toward eachother,but such relative movement of the struts 19 and 20 is prevented by thelocking bar 21 which holds the struts in parallel relation. Thus, thestruts 19 and 20 act as rigid members when locked by the locking bar 24.

After a series of the form jacks 14 have been mounted between the floorjoists 10 and 10 and locked in place, the form boards 13 are mounted onthe stanchions 17 and 18, the mat 16 of reinforcing rods placed over thejoists and form boards and the concrete slab poured over the form boardsand joist to complete a floor. When the concrete has set, the form-jacks14 are removed in the manner illustrated in Figure 7 and the form boards13 stripped from the underside of the concrete slab. To remove aform-jack the locking bar 21 is turned to the position illustrated inFigures 6 and 7 so that the pins 53, 54 and 55 extend transversely ofthe spring strips 40 and 46 and the locking pin 56 aligns with the keyhole slot 52. A downward force on the locking bar 21 against the springstrip 40 causes it to ex and tilt stanchions 17 and 18 inwardly which,in turn, causes the spring strip 46 to ex and hinge the struts 19 and 20intermediate their ends. Such hinging of the struts 19 and 20 shortensthe length of the jack 14 so that the feet 28 slip over the bottomflanges 12 of the joists 10 and 10 and the formjack falls to the floorbelow. The locking bar 21 is shown in Figure 7 being manually actuated,but in practice the locking bar would be pulled by an extension polehaving suitable fingers for engaging the handle pin 57. The form boards13 are then stripped from the concrete slab. A number of form-jacks 14must be provided corresponding to the number required to support formboards 13 for ve different oors so that successive floors may be laidwhile the concrete of the lower floors is setting.

It will now be observed that the present invention provides a hingedform-jack of improved construction which facilitates the insertion andremoval of the jack to and from the joists with which it is used. Italso will be observed that the present invention provides a form-jack ofthe type indicated which is resiliently held in its normal extendedposition, but yields to hinge the jack intermediate its ends to adaptthe jack to be inserted and removed. It will be further observed thatthe form-jack of the present invention may be easily and quicklyadjusted to t joists of different heights and spacings. It will also beobserved that the improved jack facilitates the locking and unlocking ofthe jack in position. It will still further be observed that the presentinvention provides a form-jack of the type indicated which is of simple,cornpact rugged and lightweight construction which may be economicallymanufactured and is reliable in operation.

While a single embodiment of the invention is herein illustrated anddescribed it will be understood that modications may be made in theconstruction and arrangements of elements without departing from thespirit or scope of the invention. Therefore, without limitation in thisrespect, the invention is deiined by the following claims.

I claim:

1. A removable support for holding concrete form legs and each memberhaving a hinge intermediate its ends; one of said members having itsends pivotally con-- nected to the legs, said members hinging to adaptthe legs to be inserted between the anges of the spaced I- beam joists,a locking bar movable in aligned holes in the members and havingshoulders engageable with the opposite sides of the members to lock thesupport in position between the beams, and means for releasing theengagement of a locking shoulder withone side of one member to permitthe members to hinge when the support and lform boards are to beremoved.

2. A removable support for concrete forms comprising spaced stanchions,spaced upper and lower struts extending transversely between saidstanchions, the upper strut having separate sections with its outer endspivotally con-l nected to the respective stanchions, the lower struthaving separate sections with its outer ends rigidly connectedY to therespective stanchions, spring hinges connecting the inner ends of thesections of the upper and lower struts which normally hold the struts inspaced relation and yield to permit the struts to hinge, a locking barextending through the spring hinges of the upper and lower struts andhaving shoulders overlying the opposite sides of the hinges to lock thestruts in spaced relationship, and

a slot in the hinge of the lower strut for releasing the shoulderoverlying the lower strut to` permit the struts to buckle relative toeach other and collapse the support.

3. A support for concrete forms comprising a stanchion at each end,upper and lower struts extending `between the stanchion, each strutcomprising separate rigid sections with adjacent ends of the sectionsconnectedbyL aspring strip, the opposite ends of the upper strut beingpivotally connected to the stanchions and the opposite ends of the lowerstrut being rigidly connected to the. stanchions, and a locking barextending through the. spring strips and having lugs movable intolocking and unlocking engagement with the sides of the spring stripskwhereby to adapt the support to be flexed for insertionv and removal andthe struts locked to prevent flexing.

4. A removable support for concrete forms in accordance with claim 1 inwhich means are provided for adjusting the height of the stanchions toaccommodate L,

beam joists of diterent heights, and means for adjusting the length ofthe spaced members relative to the legs to adjust the length of thesupport.

5. A support for concrete forms in accordance with claim 3 in which thestanchions are in the form of inverted U-shape yokes, the rigid sectionsof the struts are channels positioned between the sides of thestanchions, the ends of each section of the upper strut being pivotallyconnected to the stanchions by single pins extending through alignedholes in the sides of the stanchions and anges of the channels, and theends of each section of the lower strut being rigidly connected to thestanchion by a plurality of pins extending through aligned holes in thesides of the stanchions and anges of the channels.

6. A support for concrete forms in accordance with claim 5 in which theflanges of the channels of each section have a plurality of spacedaligned holes whereby the length of the support may be adjusted in lixedincrements by inserting the pins through different holes in the anges ofthe sections.

7. A support for concrete forms in accordance with claim 6 in which theinverted U-shape stanchions have foot plates attached to the lower endswhich extend laterally from the stanchions.

8. A support for concrete forms in accordance with claim 6 in whichinverted U-shape adapters are provided having spaced sides overlying thesides of the stanchions and a cross-piece overlying the top of thestanchion, said adapter plate being connected to the stanchion by spacedpins extending through the sides of the adapter and stanchions, and saidadapter having a plurality of spaced aligned holes for cooperation withthe aligned holes in the stanchion whereby the adapter may be attachedto the stanchion at dilerent heights.

9. A support for concrete forms in accordance with claim 3 in which thelocking bar is a rod extending through aligned holes in the springstrips of the struts, pins extending through the rod at opposite sidesof the spring strips of the upper and lower struts, said hole in theAspring strip of one of the struts being in the form of a key holehaving a slot at one side through which a pin may pass to permit thespring strips to flex, and a handle for raising and turning the rod.

l0. A support for concrete forms in accordance withv References Cited inthe le of this patent UNITED STATES PATENTS 2,557,693 Sachleben et al.June 19, 1951

